I was looking to expand my cache pool with a few SATA SSDs, so I attempted to move my existing four SATA HDDs to my disk shelf. (These were my first four disks before getting the shelf, hence still on SATA) What I discovered was that the SATA ports append the 'WDC_' tag on the front of the drive serial number, where as the the disk shelf drops the tag at the beginning:

 

 

I overlooked this at first, and moved the drives over to the shelf only to discover on boot Unraid could not find the drives based on serial number, instead they were in unassigned devices minus the WDC_ tag. When I tried to assign them to the correct slot, they were treated as replacement disks and naturally since four drives went missing it would not mount. I swapped the drives back and the array mounted normally.

 

So, now I am in a conundrum. I need to swap them out, but I'm thinking I need to get a spare drive and do a drive replacement one at a time, which will likely take days. Do I have any other alternative at this point?

Tools - New Config will let you assigne any disks you want to whatever slot you want, and optionally (by default) rebuild parity.